It will be replaced with a variety of classes ranging from a few minutes to an entire week as different subjects are combined.

For example, language and music could be taught jointly so the pupils could learn a song in French. Or PE and science teachers could present joint lessons on anatomy.

Core subjects such as history and geography will be cut back to give teachers more 'freedom' over the content of their lessons.

New topics will be added, including climate change, the slave trade, Mandarin, Urdu, personal finance and practical cookery.

The shake-up, endorsed by Education Secretary Alan Johnson, marks the biggest upheaval in secondary education since the national curriculum was introduced in 1988.

The Qualifications and Curriculum Authority, which drew up the proposals, said they were needed to help pupils aged from 11-14 adapt to a 'changing society'.

But critics claimed they put too much emphasis on 'issues' and 'life skills' at the expense of basics such as fractions, decimals and key historical periods.

They said the reforms harked back to the discredited teaching methods prevalent in the Sixties and Seventies, when traditional subjects were scrapped and merged to create 'integrated' lessons.

This approach was blamed for leaving children with glaring gaps in their knowledge and blighting the prospects of a generation. In further reforms, pupils will be given the chance to mark their friends' work or even their own in a shift towards 'peer assessment' and 'self-assessment'.

Pupils will also have to complete 12 key 'life skills', which include making a 50-mile unaccompanied journey by bus or train.

Mr Johnson's predecessor, Ruth Kelly, ordered the shakeup in the hope of giving teachers time to ensure students were mastering the three Rs.

Ministers had been warned results in English and maths GCSEs would nosedive unless pupils had a stronger grounding in the basics. But just as teach-ers were promised greater flexibility to make room for catchup classes, Mr Johnson personally intervened to make additional topics compulsory.

As well as requiring certain 'untouchables' such as the two world wars to remain at the heart of the syllabus, he also demanded a focus on global warming, the effects of the slave trade, financial literacy and languages from emerging global economies.

However large swathes of detail in the existing curriculum have been relegated to optional status in a draft replacement, which is out for consultation with a view to being implemented in September 2008.

In the meantime, schools are being urged to adopt a new approach to timetabling by scrapping conventional lessons and merging subjects.

The aim is to encourage more pupils to stay on in education after 16 and reinvigorate the 'backwater' first three years of secondary schooling.

Mick Waters, QCA's curriculum director, insisted the 'basics' would remain, declaring: 'Anne Boleyn will still be beheaded, the Battle of Trafalgar will still have taken place in 1805, the Pennines will remain the backbone of England and Romeo will still fall in love with Juliet.'

But he said the review aimed to 'move away from an overconcern with content'.

Prep school headmaster Chris McGovern, an education adviser to the former Tory government, said Mr Waters's claims 'disguised a revolution' in education which was undermining core subjects.

'The curriculum is moving away from subject content and knowledge towards issues such as climate change and various life skills,' he said. 'For example, history is now defined in terms of skills and concepts, and how you can improve the mental health of children through studying history.

'There is going to be a free-for-all, and with the emphasis on personal development and political correctness, content is going to be even more downgraded.

'Subject knowledge is thin already and this will make it thinner.

'This seems to be going back to a lot of what was called the " integrated" curriculum in the Seventies.'

He claimed the switch from rigid timetables would be unworkable, adding: 'In many schools you simply can't play around with the timetable in the way they're suggesting.

They're just not that flexible-Mr Johnson insisted: 'The curriculum should evolve to meet a rapidly changing world, and enable teachers to teach in a way that will continue to interest and enthuse their pupils.

'The new draft curriculum is designed to create greater flexibility for schools so they can ensure pupils master the basics as well as offer more stretching opportunities for those who excel.'